In common internal combustion engines, fuel injector systems are used to inject highly pressurized gasoline directly into combustion chambers of the internal combustion engines. An injector must be inserted deep into an internal combustion chamber of an internal combustion engine to improve the efficiency of the engine. Such a fuel injector in common internal combustion engines typically has a length of about 90 mm. Due to the restricted space in the cylindrical volume inside the cylinder block and densely arranged equipment around the cylinder head, which also limits the space available outside the cylinder block, long injectors have been designed by connecting an extension portion to such a common fuel injector. In particular, by connecting an extension portion to a common fuel injector, the length of the fuel injector can be extended from about 90 mm to a length ranging from about 150 mm to about 190 mm.
U.S. Pat. No. 7,213,578 B2 discloses a mounting structure for an injector for fuel injection into an internal combustion engine, wherein a fixing member is inserted into a hole of a cylinder head in an axial direction. Thus, the injector is fixed between the fixing member and the cylinder head. A connector portion of the fixing member is inserted into the hole of the cylinder head together with the fixing member, and the connector portion of the fixing member is connected to a connector portion of the injector. A first socket provided on an end of the connector portion of the fixing member opposite from the injector is disposed outside the cylinder head, wherein this socket is connected to a power source.